Method of crushing ores with explosive energy released in a liquid medium, and apparatus therefor



Se t. 21, 1965 L. E. WHITHAM 3,207,447

METHOD OF CRUSHING ORES WITH EXPLOSIVE ENERGY RELEASED IN A LIQUID MEDIUM, AND APPARATUS THEREFOR Filed Aug. 22 1963 3 Sheets-Sheet l INVEN TOR. LATHAM E. WHITHAM ATTORNEYS Sept. 21, 1965 E. WHITHAM 3,207,447

METHOD OF GRUSHING ORES WITH EXPLOSIVE ENERGY RELEASED IN A LIQUID MEDIUM, AND APPARATUS THEREFOR Filed Aug. 22, 1963 5 Sheets-Sheet 2 IN VEN TOR. LATHAM E. WHITHAM n g BYIM T 3 4M 80b 79 /7 ATTORNEYS Sept. 21, 1965 E. WHITHAM 3,207,447

METHOD OF CRUSHING ORES WITH EXPLOSIVE ENERGY RELEASED IN A LIQUID MEDIUM, AND APPARATUS THEREFOR Filed Aug. 22, 1963 3 Sheets-Sheet 3 WHITHAM IN VEN TOR.

ATTORNEYS I III United States Patent 3,207,447 METHOD OF CRUSHING ORES WITH EXPLOSIVE ENERGY RELEASED IN A LIQUID MEDIUM, AND APPARATUS THEREFOR Latham E. Whitham, Hurley, N. Mex., assignor to Kennecott Copper Corporation, New York, N.Y., a corporation of New York Filed Aug. 22, 1963, Ser. No. 303,795 17 Claims. (Cl. 2411) This invention is concerned with providing a nonmechanical method of efiiciency breaking discrete pieces of ore and similar earth materials into smaller sizes. It is also concerned with providing apparatus for carrying out the method to best advantage.

Ore as it comes from the mine has long been broken to the fine sizes required for the separation of valuable minerals from barren rock by using mechanical crushing and grinding equipment of various types. Such equipment has, for the most part, relied upon the action of hard crushing, pounding, or grinding surfaces on the ore introduced therebetween. Machines for the purpose are subject to tremendous stresses and abrasive forces. They require frequent repair and replacement of wear surfaces. The cost of repairs and of replacement parts, the general inefiiciency of such machines, and the inability to closely control final and intermediate particle sizes have all led to a strong desire over the years for a better way of accomplishing the task.

The principal object of this invention is to provide for the utilization of shock waves and their associated explosive or compressive energy as a crushing force.

Outstanding features of the invention in this respect are the effective use of a liquid as a medium by which the force is applied to the material to be crushed and means to direct opposing generated forces to a central particle size reduction area.

In accordance with the invention, advantage is taken of autogenous grinding and of the well known inherent weakness of rock in tension and of its tendency to spall into fragments when under tension, thereby requiring only a minimum application of force for maximum size reduction. Classification of the crushed ore and removal from the crushing apparatus of a desired quantity of particles of practically any given size are inherent advantages of the operation, as is removal of various materials, such as pure metals and organic substances. From the standpoint of apparatus, comparatively little space and only a small inventory of repair parts are required while practically any type of crushable material can be handled.

Generally speaking, the apparatus will include a crusher housing forming a liquid-containing vessel; means for introducing a slurry of ore and a liquid, and preferably also a gas, into the housing; means for removing treated slurry from the housing; and controlled means for generating a series of explosions, with attendant shock waves and compressive forces, in the housing. Desirable features are a means for selectively removing quantities of ore of any given size, and a means to trap and remove uncrushable, extraneous materials, such as pure metals and organic materials, that may be inadvertently introduced into the crusher housing with the ore to be crushed.

There are shown in the accompanying drawings specific embodiments of apparatus representing what are presently regarded as the best modes of carrying out the generic concepts of the invention in actual practice. From the detailed description of these presently preferred forms of apparatus, other more specific objects and features of the invention from the standpoints of both method and apparatus will become apparent.

Patented Sept. 21, 1965 ice In the drawings:

FIG. 1 is a view in vertical axial section of one form of apparatus of the invention embodying electrical discharge nodes as the means for generating a series of explosions with their attendant shock waves and compressive forces;

FIG. 2, a corresponding view of another form of apparatus embodying explosion discharge means utilizing a chemical explosive agent, the discharge means being shown greatly enlarged with respect to the crusher housing;

FIGS. 3A and 3B, diagrams of representative electrical control circuits usable with the electrical discharge nodes of FIG. 1;

FIG. 4, a diagram of an exemplary electrical ignition control circuit for use with the discharge nodes of FIG. 2;

FIG. 5, a fragmentary view in elevation and vertical vaxial section of apparatus equipped with an automatically operated, extraneous-material-removal chamber, the control system of which is shown diagrammatically;

FIG. 6, a somewhat similar view showing another form of automatically operated, extraneous-material-removal chamber;

FIG. 7, a horizontal section taken on the line 7-7 of FIG. 6 and showing the removal chamber in top plan;

FIG. 8, a similar view taken on the line 88 of FIG. 6; and

FIG. 9, a fragmentary vertical section taken on the line 99 of FIGS. 6 and 7.

Referring now to the drawings:

In the construction shown in FIG. 1, the crusher housing 10 is composed of a plurality of stacked cylindrical units 11, interconnected by an expandable rubber annulus and held tightly together by bolts 12 interconnecting flanges on the units. As shown, a gravity feed system is used to maintain flow of slurry through a vertically positioned crusher housing, but it should be apparent that the crusher may also be placed horizontally or put in any desired intermediate position, so long as means are provided to force continuous full flow therethrough.

The upper unit 11 is capped at 13, and a chute 14, through which ore to be crushed is supplied, enters the top portion of the unit. Water inlet pipe 15 is also provided at the top portion of the upper stacked unit 11 near the uppermost level of the discharge end of chute 14 and an air inlet pipe 16 connects therewith so that water and entrained air can be supplied the interior of the housing, as required. Additional air inlet pipes 16 supply air to the crusher units 11 directly as shown or with back-wash water as will be explained.

The lower stacked unit 11 discharges into tank 17, and ore particles that are sufficiently small pass through the holes in a classifying screen 18 and are removed through an outlet conduit 19. Those particles too large to pass through classifying screen 18 are retained thereon until they have been further reduced or removed, as will be described. Although a screen is illustrated, it should be apparent that other classifying devices such as punched plates or properly positioned bars could be employed instead.

Ore passing through outlet conduit 19 is used, treated, or classified, as desired, and conventional structure can be employed for the purpose.

A back-wash pipe 20 is shown entering the bottom of tank 17, although, if desired, other such back-wash pipes can be placed at any position along the length of the housing 10 to introduce back-wash water. In the illustrated arrangement the back-wash water entering through pipe 20 percolates upwardly through the housing and carries ore fines out fines-discharge conduits 21. As previously noted, air from inlet pipe 16 can also be entrained in the back-washwater to increase the sponginess of the ore-'water-air'siurry.

Discharge nodes 22 are fixed to each unit 11 and to the tank 17, and these house the explosion-generating.means necessary for reduction of .ores passed through thehousing; Each'of the nodes includes a flange'23 adapted to be e lo h e t r Qflh nits .1 1 tan dr o surround iopeningsj formed through the wall thereof.

Since they may have' to be removed, inspected, and replaced, the nodes are preferably attached with. bolts. or the like, not shown, and, if necessary, are reinfo rced with removable bandssurrounding them and the crusher h u n f j Although the discharge nodes'22 are'illustrated as being oppos el P S li B d. and e e yrp c along-the lengths ofstacked units llffilld this has been fo'und tobe a very efiicient arrangement, other'node placementsican b m d. d for Partic lar si u t o may even; be

preferred. With the placementshown, however, a simultaneous explosion generated at two or more of the nodes 22, in the s ame plane, willresultin both shoclg waves and explosive or compressivetorces'from two or more sides contacting "the ore particles positioned therebetween.

Repeated sharp blows from multiple shoel; waves greatly 1.

increase the reverberating tensile forces set. up in'the rock particles and tears them apart: The greater 'the number' of .firing nodes simultaneouslydischarged in the same plane,"the greater the number of shock waves that strike the rock particles to create additi onalitensile stresses if therein; Furthermore, inaddition to the reverberating forces set up in the. ore particles as aresult of thepsharp impact blows of the individual shock waves; the oppositely placed explosion-generating means, when discharged, create explosive forces thatmove the ore particles toward the center ot the crusher housingwhere they are put in tremendous compression and are ground against each other. This autogenous grinding action greatly'furthers the particle size reduction process; The a I use of simultaneously discharging oppositely placed explosion-generating means that compress the ore in'the center'lof the housingalso minimizeswear on and in creases-the" life of theinterior housing wall, since the ore-particles are not'bouncedfthereoff. 1 To further' protect the inner wall of the housing and/ or the discharge-nodes from damage that may result 'from the slurry flowingtherethrough, it maybe necessary to coat it with ceramic, plastic," or rubber,'-as sl1own at 23, inside the upper stacked-unit 11'; Such a lining may also be require'd'i'n' those instances where the discharge nodes are not placed opposite'one another'and a resilient materialis required to dampen-excessive shock on the crusher walll 2. In initiatingoperation of the crusher, valve 24 in outlet conduit 19 and the control valves'25 inthe fines-discharge conduits 21 are closed, and valves '26 and 27 in-waterinlet pipe '15 ar1d back-wash pipe 20,'respectively,= are 'o'pened to'fill the housing with water to afpoiht above the level of the uppermost" discharge :riodes. Air 'is" introduced desired density, as determined by visual observation "or by one or more; conventional type density measurement devices (not shown mountedon the housing; the valves 24, 25, 26, and 27 are manually or automatically opened to allow flow into and out of the'crusher at such'a rate that t e c sher ema ns f i lu r lo de r d nsi y to a level above the uppermost discharge nodes.

Theair introduced through inlet pipe 16 forms voids in the slurry and makes it somewhat spongy, and as the explosions are simultaneouslygenerated opposite one anot e yom ress theyspon'gymass, including the air thereinf: 'Thi sfm'ass quickly expands under the influence of the compressed air' after the compressive force has passed, and the rapid expansion further increases attrition between particle's,"g'reatly. adding tothe speed and efficiency of ore particle size reduction. As the ores are crushed and removed frornthe crusher, additional ore is introduced through funnel 14, and make-up water and air .1'6 addedas required through thewater and air inlets..

, In m y o i u in prslw s t as-bee f und I desirable; to gcontinuef ultra-fine'particles inthe flow process, sincethe'particle srpay hinder working of the remaining material. Furthermore, when it is desiredto reduce the. ore particles to a given size, continued reduction will render them so smalbastobeunusable for manypurposes an a n fiie entww of me t n w .To avoid the problems'incident the obtaining of-ultrafine particles and of maintaining them in the flow process, an inexpensiveiand simplemeans is provided .to remove them as they'arereduced. todesired size.* This is accomplished by supplyingback-wash water through back-wash pipe 20 and removing itwith the ore particles of desired s-ize through fines-discharge conduits 21 The clear Water entering'under pressurethrough pipe20 percolates upwardly through theslurry, picking up the lighter ore particles as it moves. The quantity and size of the particles removed are controlled 'by the volume of back-wash water used and the pressure at which it is supplied. Main-flow s lurry'moving downwardly through the crusher housing is prevented from flowing out the fines-discharge conduits by the baffie llq formed by the in-turned bottomfof each unit, and if no .othermeans are provided to regulate flow of slurry through the crusher, the degree of in-turn offthe unit bottoms will determine the rate of flow therethroug f v .A seal is required betweeneach pair of adjacent stackedunits 11Jand this; preferably takes the form of the resilient seals 29 illustrated in FIG. 1. Seals 2 9 are each fixed at one end tofth'e interior of the bafile 11a of an upstream unit 11,1 foldedinto the housing, and fixed to the exterior of a curved flange 30 of. an adjacentdownstream unit. jThe bottom edge of thebaffie of the upstream unit tightlyabuts'the seal and forms a completely enclosed pocket 31. H r r v v j Fines-discharge conduits 21, previously described, intersect the crusher housing at the curved flanges 30 so that mainstream slurry is'additionally deflected by the seal 29. f Eachpoeket 31 'formedby the fold of a seal is provided with an air pressure conduit 32, the other'end 'of which is connectedto a source of pressure, not shown. A standard two-way supply and exhaust valve 33 controls flow of pressurized air tothe pockets through conduits 32, or

f o l -he P ck t o tm s erafi e Whenvalvejs 33 are opened to admit pressurized air to the pockets, the'sealsexpand to restrict the opening between adjacent units 11', the amount of pressure applied determiningjthe degree of; restriction. This control is desirable during the initiation" of crushing operations and at Qther times'when itisdesired .to operate only some of the firingno des and to reduce the rate of slurry flow through the housing. t p 1 ..Tanl 11 isalso provided with discharge nodes 35 housing eXpIbSiOgenemting"means whichcooperate with j Screen-18 and backwash-pipe 20 to insure reduction to desired si'ze' of all particlesnot sufficiently reduced during their passage thrdugli' the'housi'nfg. "Screen 18 prevents oversized paru esgpassingtcrhe outlet conduit 19, and

water fromback-wash pipe 20 agitates-them so that they can be'further reduced by repeated firings of nodes 35. As they are reducedto size, the particles are either removed via the fines-discharge conduits 21 with the backwash water or through screen 18 and outlet conduit 19.

Organic material-s, pure metals, and the like, that ar uncrushaible will be retained on screen 18 and can be easily removed either manually through an inspection door 36 or automatically, as will be further explained.

Although the crusher shown in FIG. 1 constitutes a preferred form of the invention, it should be apparent that solids to be reduced in size, water, and air can all be introduced in other ways and at other points along the crusher. A plurality of feed arrangements can also be used to supply additional solids, water, or air as required. Similarly, the back-wash pipe can be positioned at various points along the crusher housing, more than one such back-wash pipe can be provided, or for .some cases no back-wash pipe need be provided. In the latter instance, all of the ores would be removed from the bottom of the crusher and classified, and those requiring further size reduction recirculated through the housing.

The discharge nodes 22 of FIG. 1 each include a shell 37 of hollow, semi-spherical configuration the peripheral edge of which surrounds an opening 38 in the wall of units 11 or tank 17.

A pair of ground terminals 39 are fixed to shell 37 and an insulated ignition or power terminal 41 extends therebetween. As an electrical discharge is communicated between the ignition and ground terminals, the resulting explosion initially generates shock forces and then explosive or compressive forces that radiate outwardly from the source, i.e. the terminals, in all directions. However, the shock waves and compressive forces contacting the semi-spherical shell, because of the configuration of the shell, are directed back into the crusher to assist in the desired ore reduction. This results in the explosive forces becoming, in effect, a tremendous implosive force at the center of the crusher.

Although this embodiment of the invention has been disclosed as utilizing an electrical discharge means to create the forces required for ore reduction, it should be apparent that chemically generated shock waves and accompanying compressive forces can also be used in many instances.

Referring now to FIG. 2, wherein another embodiment of the invention, utilizing means to chemically generate shock waves and compressive forces, is shown. In this embodiment, the stacked crusher units, designated 45, are of truncated top formation, open at the top and bottom and interconnected for continuous flow therethrough. The lowermost stacked unit discharges into a similarly shaped, but preferably larger unit 46, and slurry is carried through outlet conduit 47 connected to the bottom of unit 46 to a point of use. Oversized ore particles passing out of the crusher through conduit 47 are recirculated from the housing top, or, if so desired, any intermediate point along the housing.

As with the previous embodiment, a classifier can be placed above outlet conduit 47 and across the bottom of the lower unit to prevent passage of oversized particles and one or more inspection and removal doors (not shown) provided as required. When the classifier is provided, water entering through back-wash pipe 48 continues agitation of the particles until they have been reduced to the desired size by the inwardly directed shock waves and compressive forces created through repeated firings of the explosion-generating means 49 afiixed to lower unit 46.

Fines-discharge conduits 49a extend outwardly from connector cylinders 50 which serve to position the bottom of each truncated top-shaped unit for discharge into the open top of the one below. Thus, the in-turned lower portion of each truncated top serves as a bafiie to prevent main flow slurry escaping out the fines-discharge conduits. Back-wash water and additional air, if needed, are supplied through pipes 48 and 51, respectively, the volume and velocity of the back-wash water determining the size and number of fines removed through the back-wash outlets.

The curved wall configuration of the truncated topshaped units serves to direct disintegrating shock waves and explosive forces to the center of the housing, and a separate semi-spherical discharge node shell is not required with this type housing.

The explosion-generating means illustrated in FIG. 2 comprises a curved flange 52 detachably mounted on the truncated top-shaped units in desired arrangement, but preferably opposite one another as shown. A valve housing 53 is fixed to each flange and a passage 54 extends through the valve housing and the flange to communicate with a port 55 passing through the unit wall. A spark plug 56 is fixed to and extends through the flange and into the unit to ignite the explosive chemical supplied through the valve. The spark plug operates in the same manner as the spark plug used in an internal combustion engine. The chemical used for generating an explosion may be gas, liquid, or solid, as desired, but a more rapid discharge rate can be obtained using either liquid or gas, since they can be more rapidly and effectively fed into the firing area. The particular solenoid actuated valves illustrated in FIG. 2 best control gas or liquid and are rotated periodically to align port 57 passing through the valve head, with passage 54- and port 55. After gas or liquid under pressure has been supplied through ports 55, 57, and 54 for a set period of time, the valves are again rotated so that the ports are out of alignment and no more gas or liquid can pass through.

After the gas or atomized liquid (atomized by the use of a conventional canburetor, not shown, in the inlet line) has been supplied the housing, the spark plugs are fired and an explosion, with its incidental shock waves and compressive forces occurs. A timing circuit, an exe-m plary one of which is to be more fully disclosed, controls operation of the valve and firing of the spark plugs.

It should be understood that the electrical explosiongenerating means disclosed in conjunction with the embodiment of FIG. 1 can be used with the crusher of FIG. 2, and the chemical explosion-generating means disclosed in the embodiment of FIG. 2 can be used in the crusher of FIG. 1, preferably with a semi-spherical shell serving as the generating means housing to properly direct shock waves and compressive forces toward the center of the crusher housing.

FIGS. 3A and 3B exemplify electrical control circuits that can be used to control electrical discharges for crushers employing electrical explosion-generating nodes.

Looking first at FIG. 3A, wherein a typical crusher housing is shown fragmentarily at 60 and a typical semispherical discharge node at 61. A pair of ignition control terminals are provided at 62, and an insulated power terminal is shown at 63. The circuit includes a threephase delta-zig-zag transformer 64, the secondary side of which is grounded at 66 and which is connected through line 67 having a protective circuit breaker 68 therein to a thyratron tube controlled rectifier 69. A step-up transformer 70, grounded at 71, is positioned in the line 72 interconnecting the step-up transformer and the power terminal 63. The timing of discharges between the power and ground terminals is regulated by a phase shift timer 73 that periodically establishes a pilot arc which in turn initiates power discharge. Power for the timer is supplied through line 74 which is time phased sixty electrical degrees ahead of power supplied through line 67.

While the positive half of the sine wave in the illustrated example is rectified for use at one terminal, the negative half of the sine wave may be equally well utilized for power at another terminal, since there is a common ground return.

Furthermore, although here illustrated as a control circuit for an individual discharge node, it should be clear that the same circuit could sequentially power and time the discharge of as many nodes as desired, so long as no two of them are positioned in the same crushing level. Discharge nodes placed at a level for simultaneous firing 7 fmustb'e on independent power transformers and circuits. It isno' t necessary .to have separate power transformers and related equipment for each level of terminals, but only for individual terminals" operating at the same level.

It is also possible, and in some instances may prove desirable, to employ different gradients of voltage at various levels ofdischarge nodes along the length of a crusher to efliciently utilize different energy levels. For example, at'the first stage nodes of the crusher, where the material isrelatively coarse, it might be desirable to utilize very high levels of input energy controlled to develop a low shock wave force and a large compressive force. At intermediate stage nodes, the power requirements can be materially reduced with an appropriate division of energy, and at final stage nodes, minimum power with resultant maximum shock wave intensity will be employed.

The different p'ower'levels will permit maximum effective use of bothshock waves and compressive forces toobtainthe most desirable crushing effects onthe ore particles in the crusher. l

FIG. 3B represents schematically another form of control circuit that can be utilized with the electrical discharge 1 nodes of the type illustratedin FIG. 1. The crusher shown in this embodiment is'of square configurationand v has oppositely paired semi-spherical discharge nodes of theft'ype previously disclosed. Material tobe crushed is fed'into' the top of the crusher throughhopper 76,water andair are addedthrough conduits 77 and 78, respectively, and crusher material is removed from sump 79 through pump 80 andconduit 81to cyclone classifier 82. Those fine particles that are sufliciently reduced pass out conduit 83, and those requiring further reduction are dropped back into the crusher.. Although two discharge nodes are illustrated at each stage, four could as well be provided, one, at each side of the crusher housing.

, The control circuit for the crusher of FIG. 3B, illustrated only fragmentarily since the remainder is identical with the illustrated portion, includes a six-phase secondary from three-phase primary transformer shown generally at '84, and having a common ground 85, positive half-wave rectifier. 86, and. condensers 87. Double throw switches 88 in one position connect power lines 89 with the condensers for charging and in the other position discharge the condensers through power terminals 90 and ground terminals 91. f a V I The position of the switches is determined by timer 92 which periodically completes the circuit to the solenoids 93 to reverse the switches from their normal spring-biased position shown. The sequential rate of discharge of the terminals is determined by the timer. The discharge nodes on the other side of the crusher are powered by a similar transformer and circuit, not shown, and the generated explosions are timed by timer 92 to insure simultaneous discharge of all nodes at the same level. a FIG. 4 illustrates a timer control circuit that may be used'with the chemical dischargevalve 53 shown in FIG, 2. This circuit includes a pair of distributors 94 and 95 with respective rotating contact arms 96 and 97 driven through a common shaft 98 by constant speed motor 99. Corresponding multiple fixed contacts 100 and 101 are positioned around the two distributors, and the revolving contact arm 97 of distributor 95 is set ftolag slightly behind the contact arm96 of distributor 94. Fixed contacts 100 of distributor 94 are each connected to complete 8 to'shutf- Further rotation will result in arm'97 engaging the corresponding fixed contact 101, connected to the'c'ontrol grid' 102 "of a vacuum tube 103. Positive voltage applied through contact arm 97 will change the grid bias and'allow a-direct current pulse to flow'thr'ough the'tube to the primary side of step-up transformer 104, thereby inducing a high voltage in the secondary side o f-t he transformer, which side is connected to the spark plug of the same firing unit as the valve.

Thus, after the chemical to, be exploded has been injected into the firing area of the crusher housing, the spark plug is fired and an explosion results. 7 As has been previously mentioned, foreign materials that are uncrushable are often introduced with the ore to be crushed, and means must b provided to periodically remove these materials from the crusher. Such a means, in its simplestform, may comprise a hand or man hole formed in the terminal crusher unit, butpreferably will consist of 'an automatically operated trap chamber or plurality of trap chambers of the type shown in FIGS. Sand 6. a 1 f i In FIG. 5, a terminal crusher-unit, shown fragmentarily at 105, discharges through a single trap chamber 106 to conduit 107 leading to a point of use, ort-o a classifier, as previously described. Bottom outlet 108 of unit has a flange 109 thereon, which flange is [held in sealing engagement with a corresponding flange 110 on the top of the trap chamber by a resilient pneumatically controlled sealing element 111. A'simil-ar resilient pneumatically controlled sealing element surrounds the peripheries of flange 112 on the bottom of the trap chamber and flange 113 on conduit 107. Screen 114 is positioned above the outlet conduit between flanges 112 and 113 and is held in place'by a raised rim 115 surrounding flange 113, the rim being in sealing engagement with the bottom of flange 112. v a I A sensing .unit 116 having a pair of probes 1 17 extends into the trap chamber, and a control circuit is completed by material-accumulating in thechamber to the level of the probes. The control circuit, when closed, act-mates timer 118 to position two-way valve 119 and 120 to exhaust :air from the interior of sealing elements 111 and reversible motor 121 to slide the chamber toward its dotted line position. Thisaction first moves port 122, which extends through flange 110, out of registration with outlet 108 to seal off the bottom outlet 108. Water and crushed materials continue to flow out port 123, extending through flange 113 and conduit 107, for a short periodoftime after the bottom outlet'108 is closed, since port 123 will continue, in registration with outlet 108. Thus, the only material remaining in the trap chamber consists of uncrus'hed material that cannot pass through the ,mesh of screen 114. qMotor 121 continues to slide the chamber until the port 123 is clear'offlange 113 and screen 1114, "andpthe ,uncrushed material is released. After :a predetermined period of time, the motor 121 is reversed by timer 118,- and the chamber is moved, back to its full line position in the slurry, flow path, and the valves 119and 120 are positioned to again allow air pressure into the sealing elements to insure a tight seal between the crusher, the trap chamber, and the outlet conduit. To further insure a tight seal and. permit easy sliding ofthe trap chamher, the abuttingfaces of the flanges 109,:110, 112,'and 113 are coated .with Neoprene orother similar material.

'A shield 124, fixed to the chamber Wall, prevents damage to the sensing unit 116 and also prevents inadvertent completion of the circuit through probes 117 byincoming slurry.

FIGS. 6-9 show a modification wherein a plurality of trap 'ohambers are arranged for successive filling with uncrushable material and for automatic dumping of'the material accumulated I The -trap chambers 125- are of cylindrical configuration and are positioned in a circle surrounding hub 126.

Arms 127 rigidly interconnect the hub and the trap chamhers for movement together. Top flange 128, which overlies the top of the chambers, is fixed to hub 126 and is in face to face sealing enbagement with flange 129 which is solidly mounted on the lower end of bottom outlet 130 of the fragmentarily shown crusher 131.

A bottom flange 132, similar to top flange 128, underlies the chambers and is fixed to hub 126, and is in face to face sealing engagement with immovable flange 133 fixed to discharge conduit 134.

Hub 126 is journaled for rotation at its upper end in a fixed support 135 at its lower end in flange 133, and passes freely through flange 129.

A motor 136, acting through reduction gearing in box 137, pulleys 138 and 139 fixed to the motor shaft and the hub, respectively, and V-belt 138a, continually rotates hub 126 slowly in a counter-clockwise direction. This moves the trap chambers successively into position beneath bottom outlet 130. As each trap chamber is moved into position, its port 140 through top flange 128 is aligned with bottom outlet 130 and the material from the crusher falls therein. Material that has been sufliciently reduced to pass through screen 141 passes out of the chamber through port 142 in flange 132 and discharge conduit 134. Since port 142 is larger than port 140, flow of liquid and small ore particles continues through discharge conduit 134 even after port 140 has passed out of registration with bottom outlet 130, and inflow to the chamber has been blocked off. Continued rotation of the chamber results in sealing of discharge conduit 134 and the dumping of material retained on screen 141 through an appropriate opening (not shown) in flange 133.

While various forms of crusher units have been illustrated, they do not represent the only forms that may be used, and in some instances, it may be desirable to combine two or more forms into a single crusher. Thus, it may be desirable to utilize a spherical unit that gives maximum efficiency and ore particle size reduction with a truncated t-op shaped unit, wherein the crushing efliciency is not as good and the ore particle size reduction is not so complete. Each crusher must be individually designed for the particular operating conditions, and factors such as the available power, the hardness, malleability, etc. of the ores, and the degree of ore reduction desired must all be considered, but the designs must incorporate the basic design criteria set forth and illustrated in the present application.

It has been discovered, for example, that electrically generated explosions result in shock waves having a steeper front than do chemically generated explosions. Thus, in designing a crusher, it may be desirable to employ electrical force generating means during initial reduction stages when large rocks are to be shattered, and chemical force generating means after the ore has been partially reduced, or to employ either the electrical force generating means or the chemical force generating means separately. This choice may also be governed by the costs or availability or non-availability of one or the other of th power sources.

Whereas there are here illustrated and specifically described certain preferred procedure and construction of apparatus which .are presently regarded as the best modes of carrying out the invention, it should be understood that various changes may be :made and other construction-s adopted without departing from the inventive subject matter particularly pointed out and claimed herebelow.

I claim:

1. A method of crushing massed discrete pieces or particles of solid materials such as ore, comprising the steps of: mixing the material to be crushed with a liquid to form a slurry; passing the slurry through a confining vessel, while maintaining said vessel substantially completely full of the slurry at all times; periodically generating ex- 10 plosions in said slurry at spaced intervals along the confining vessel; and directing the shock waves and compressive forces resulting from said explosions toward the interior of the vessel, whereby shock waves propagate in the liquid, contact the solid material to be crushed, and set up reverberating tensile stresses therein.

2. The method of claim 1, wherein air is introduced into the slurry in advance of the explosions, and wherein the explosions are generated simultaneously at opposite sides of the material to be crushed, thereby forcing portions of said material toward the axial center of the vessel and into contact with other portions thereof, with resultant autogenous crushing, the air being compressed by the opposing explosive forces and rapidly expanding as the explosive forces decrease, thereby augmenting the autog enous grinding action.

3. The method of claim 2, wherein those portions of the material to be crushed which are not reduced to desired size are retained in the vessel and are continually subjected to shock Waves and compressive forces created by repeated explosions.

4. The method of claim 2, wherein portions of the material to be crushed and extraneous materials introduced therewith which are not reduced to desired size during travel of the slurry through the vessel are accumulated in the vessel and are then removed separately from the slurry traveled through the vessel.

5. A crusher, comprising: an elongate housing forming a liquid-containing vessel; means at one end of the housing for introducing material to be crushed; means for introducing a slurry-forming liquid into said housing; outlet means for slurry at the other end of said housing; a plurality of explosion-generating means spaced along the length of the housing; and means for periodically actuating said explosion-generating means to create shock waves and compressive forces in the slurry, whereby the material to be crushed is subjected to repeated shock waves and compressive forces as it passes through the housing.

6. The crusher of claim 5, wherein means to introduce air into the housing are provided; another explosion-generating means is mounted on the housing in opposing relationship to the first explosion-generating means; and wherein the actuating means simultaneously actuates the opposing explosion-generating means so that slurry passing between them will be compressed in the center of the housing and the material to be crushed will be contacted by a plurality of shock waves and compressive forces.

7. The crusher of claim 5, wherein the housing is constructed of a plurality of interconnected units, said units each being surrounded by explosion-discharge means and wherein said actuating means simultaneously actuates all of the explosion-generating means on one unit.

8. The crusher of claim 5, wherein a trap chamber having a filling and a dumping position is provided at the outlet end of the crusher, the slurry outlet means from the crusher housing being adapted to discharge through an opening in one end of the trap chamber when the trap chamber is in its filling position; another opening is provided through the bottom of the trap chamber; an outlet conduit is positioned beneath the trap chamber; said opening being positioned above the outlet conduit in the filling position and above a large material receiver in the dumping position; and means are provided to move the trap chamber between filling and dumping positions.

9. The crusher of claim 7, wherein said units are stacked on top of one another and the bottom of each unit is turned inwardly to regulate the volume of slurry passing through the housing.

10. The crusher of claim 7, wherein the outlet means for slurry from the crusher housing opens into one side of a tank; an outlet conduit is positioned on the opposite side of the tank; a classifier means is positioned intermediate the said sides of the tank to prevent flow of solid particles larger than the retaining limit of the classifier means to? the "outlet'conduit; and means are'provided for-removingmaterial retained'bythe classifier; l i

-- lL-The erus'her-ofclaim 8,- wherein -the-'tr'ap chamber crusher to the level of-the electrodes completing'said' 'cir cuit to init'iate operation of the timerand -the motor whereby said motor-first moves the trap' chamber to'its dumping position andthen moves it back 'to"-its*- filling position-. a 1 A I 12-. '-The crusher of claim 8,-wh'erei'n the-trap chamber consists of a plurality of receivers continually moved into filling anddumpirig position by'the 'positi-oningjmeahs. 13'; The crusher'of claim 9, Wherei'nthe'explosion gen eratingmeans inclu'des'a cont-r01 valve for admitting-ex plosivechemicals to the crusher;actuator-means for .the control valve; and a sparl; plug positioned to' detonate the explosive chemicalsupplied thecru'sherQ- 1 14. The crusher of claim'9,-'whereiri the units are cylindrical'and' the explosion-generating means include semispherical shells 'rnounted onthe-wall of said uriits; with the peripheries" of'said shells surroun'ding openings in said wall; a power terminal extending through" 1said"she11; a" ground terminal extending through and connected to said shell; fandici rcuitf means, adapted to create an electrical 12. discharge between'the portions of' said powenan'd'g round electrode'swithin the unit s. L '15:"-'I he crusher-of claim'- '10,=wherein"a back-wash -pi-pe' enters' 'the tank; adjacent the downstream portio'n' "of the screen; fines-discharge conduit's arespaced' along the length of the "crusher housingyandya bafile is positioned upstream bf each fines-dischargecoiiduit'to -preventmainline flo'w of slurry out of-the" fines-discharge"conduits, whereby -'-liquidentering the crusherthrough the backwash pipe percolates upstream;throughithe slurry andcarries finelyreduced' materiarout the finesrdischarg e cona /11;. 1;; a y a: 1:. 1m. .L:.:. 5; 16. The crusher of claim 13, whe reiri"the units" are-or; truncated-topconfiguration nd" are; o e at b'oth ends.

1'7; Ih'e 'c'rusher "of :la-1ni15; wherein "additional 'eX-' pl'o'sion-generatingmeansar mounted ori'the -tank,' said additional explosion=generating means, "wh en actuated; creating sh ockwav'esand comp essive forces in said tank to further re'duce thesize of- -material "taiiied gon -the screen;-

:1; References Cited by the Examin'er Z q TED- SIATES 1?%?*IEN $T r 2,4 6,557 27: 9; iNp dcns ioldq'et al 2 1 369 a: 1 5 B r eye 1 6, 9 .5 H Im iF a 2,980,345; 4/61- 1 Kececifogluetral.

L E E tra in -X11? .1. 24.1%1;

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1. A METHOD OF CRUSHING MASSED DISCRETE PIECES OR PARTICLES OF SOLID MATERIALS SUCH AS ORE, COMPRISING THE STEPS OF: MIXING THE MATERIAL TO BE CRUSHED WITH A LIQUID TO FORM A SLURRY; PASSING THE SLURRY THROUGH A CONFINING VESSEL, WHILE MAINTAINING SAID VESSEL SUBSTANTIALLY COMPLETELY FULL OF THE SLURRY AT ALL TIMES; PERIODICALLY GENERATING EXPLOSIONS IN SAID SLURRY AT SPACED INTERVALS ALONG THE CONFINING VESSEL; AND DIRECTING THE SHOCK WAVES AND COMPRESSIVE FORCES RESULTING FROM SAID EXPLOSIONS TOWARD THE INTERIOR OF THE VESSEL, WHEREBY SHOCK WAVES PROPAGATE IN THE LIQUID, CONTACT THE SOLID MATERIAL TO BE CRUSHED, AND SET UP REVERBERATING TENSILE STRESSES THEREIN.
 5. A CRUSHER, COMPRISING: AN ELONGATE HOUSING FORMING A LIQUID-CONTAINING VESSEL; MEANS AT ONE END OF THE HOUSING FOR INTRODUCING MATERIAL TO BE CRUSHED; MEANS FOR INTRODUCING A SLURRYFORMING LIQUID INTO SAID HOUSING; OUTLET MEANS FOR SLURRY AT THE OTHER END OF SAID HOUSING; A PLURALITY OF EXPLOSION-GENERATING MEANS SPACED ALONG THE LENGTH OF THE HOUSING; AND MEANS FOR PERIODICALLY ACTUATING SAID EXPLOSION-GENERATING MEANS TO CREATE SHOCK WAVES ANS COMPRESSIVE FORCES IN THE SLURRY, WHEREBY THE MATERIAL TO BE CRUSHED IS SUBJECTED TO REPEATED SHOCK WAVES AND COMPRESSIVE FORCES AS IT PASSES THROUGH THE HOUSING. 